2008 年岩手県沿岸北部地震における強震観測点周辺の状況と発生した地震動との対応性 Damage Investigation of Surroundings of the Seismic Stations in the 2008 Iwate-ken Engan Hokubu Earthquake and Correspondence of Damage to Bulidings with Strong Ground Motions

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Abstract

2008 年岩手県沿岸北部地震を対象として,震度6 弱以上を記録した全ての強震観測点と5 強を記録した一部の強震観測点周辺の被害調査を行った.その結果,いくつかの観測点周辺で外装材の落下,外壁のわずかなひび割れ,窓ガラスの破損といった軽微な建物被害は見られたが,いずれの観測点周辺でも,大破・全壊といった建物の大きな被害はなかった.観測された強震記録の性質について検討した結果,そのほとんどが0.5 秒以下の極短周期が卓越した地震動で,建物の大きな被害と相関をもつ1-2 秒応答は小さく,このことが大きな震度にもかかわらず建物の大きな被害が生じなかった原因と考えられる.

We carried out damage investigation around the seismic stations where high JMA seismic intensity scales were recorded in the 2008 Iwate-ken Engan Hokubu Earthquake. We found some minor damage such as small cracks in the wall or damaged glass, but heavy damage to buildings was not found around all the seismic stations. We investigated the correspondence of strong ground motions with damage to buildings. Very short period below 0.5 sec. was dominated in most strong ground motions and the 1-2 sec. response which has close relationship with heavy damage to buildings was small, therefore, heavy damage to buildings was not found in spite of high JMA seismic intensity scale.

Journal

  • Journal of Japan Association for Earthquake Engineering

    Journal of Japan Association for Earthquake Engineering 10(4), 54-81, 2010

    JAPAN ASSOCIATION FOR EARTHQUAKE ENGINEERING

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